1. Field of the Invention
The present invention relates to a stamped knitting tool for textile machines, particularly knitting machines, including a shank which is provided with at least one butt and has at least one hollow space filled with a vibration damping material (such as plastic) firmly bonded to the shank.
2. Background Information
Knitting tools are here understood to mean latch needles, spring beard needles, compound needles, latch-less needles, sinkers and the like.
In order to avoid hook or head breakage which occurs with increasing frequency at higher knitting speeds or to at least reduce the frequency of breakage and thus extend the service life of the knitting tools, German Patent No. 2,820,925, and corresponding U.S. Pat. No. 4,452,053, disclose the provision of at least one easily flexible bridge piece which is provided in the shank and which is coupled to the butt to thus convert the impact energy introduced into the butt by the cams of the machine into bending work. This narrow bridge piece has a height of at most 1.1 mm and, with a length of, for example, more than 8 mm, is therefore highly elastic. In order to increase the stability of such knitting tools equipped with a greatly vibration damped shank, German Offenlegungsschrift (application published without examination) 3,014,75l, and corresponding U.S. Pat. No. 4,553,411, disclose the provision of a further, slightly flexible bridge piece or rib which is coupled to the butt and which, together with the above-mentioned upper bridge piece and with continuous guide members extending from the upper shank edge to the lower shank edge, defines at least one hollow space. All of these knitting tools have been found to be excellent in practice.
German Patent No. 3,314,809, and corresponding U.S. Pat. No. 4,562,705, disclose a modification of these knitting tools in that the shank is provided with at least one hollow space, which is closed or open at its edges and is filled with a vibration damping material (plastic) which is firmly bonded to the adjoining shank. These hollow spaces are openings or recesses which are oriented transversely to the longitudinal axis of the shank and may possibly have a profiled shape along their edges to thus ensure a firm anchor for the vibration damping material (plastic) filling. It has been found that the combination of the filling material (plastic) and the easily flexible bridge pieces which have a height of no more than 1.1 mm, favorably influences the vibration behavior of the bridge pieces in such a manner that it is possible to further increase the knitting speed while simultaneously extending the service life of the knitting tools.
In view of the openings or recesses extending from broadside to broadside of the shank and forming the respective hollow space, the anchoring of the vibration damping material (plastic) which fills the respective hollow spac can be effected only at the outlining faces of the respective hollow space. Due to the small thickness of the shank, these faces are necessarily narrow. This problem can be solved technically, but it may require special measures with respect to the edge configuration (see, for example, German Patent No. 3,706,856 and corresponding U.S. Pat. No. 4,783,976).